Coral settlement on a highly disturbed equatorial reef system.

Area of Science:

• Marine Biology
• Ecology
• Coral Reef Science

Background:

• Coral larval settlement is crucial for reef ecosystem persistence and population demography.
• Understanding coral settlement is limited in anthropogenically impacted regions like Singapore.
• Coral reefs in Singapore face significant environmental pressures.

Purpose of the Study:

• To investigate the spatial and temporal patterns of coral larval settlement in Singapore.
• To assess the role of coral settlement in the persistence of Singapore's coral communities.
• To determine the contribution of different coral families to larval settlement.

Main Methods:

• Coral settlement tiles were deployed and collected quarterly at seven sites over two years (2011-2013).
• Settlement rates were analyzed for temporal and spatial variations.
• Abundance of different coral families among settled spat was quantified.

Main Results:

• Coral settlement occurred year-round but varied significantly in time and space, with low annual rates (~54.72 spat m(-2) yr(-1)).
• Peak settlement was observed from March-May and September-November, aligning with spawning periods.
• Pocilloporidae dominated settlement (83.6%), while Poritidae (6%) and Acroporidae (<1%) were less abundant.

Conclusions:

• Current coral settlement patterns in Singapore reinforce the dominance of local, sediment-tolerant coral taxa.
• The replenishment capacity of Singapore's reefs appears constrained.
• Low settlement rates and assemblage reinforcement may lead to less resilient coral reef ecosystems.